QR code

During the month of June 2011, according to one study, 14 million American mobile users scanned a QR code or a barcode. Some 58% of those users scanned a QR or barcode from their homes, while 39% scanned from retail stores; 53% of the 14 million users were men between the ages of 18 and 34.[7]

QR codes are used in some augmented reality systems to determine the positions of objects in 3-dimensional space.[4] QR Codes are also being used to deliver Augmented Reality experiences.

QR codes can be used on various mobile device operating systems. iPhones running on iOS 11 and higher[24] and some Android devices can natively scan QR codes without downloading an external app.[25] The camera app is able to scan and display the kind of QR code (only on iPhone) along with the link (both on Android and iPhone). These devices support URL redirection, which allows QR codes to send metadata to existing applications on the device. Many paid or free apps are available with the ability to scan the codes and hard-link to an external URL.

QR Codes application in the field of Construction has already been started in India which helps in saving time, paper and energy. QR Code usage in Safety Vertical of Construction industry aids in usage of Resources, allocation of time and usage of critical information. Dynamic nature of Construction Industry requires the need for dynamic technologies and QR Code aids in developing that technology for future usages.

URLs aided marketing conversion rates even in the pre-smartphone era, but during those years faced several limitations: ad viewers usually had to type the URL and often did not have a web browser in front of them when they first viewed the ad. The chances were high that they would forget to visit the site later, not bother to type a URL, or forget what URL to type. Semantic URLs decreased these risks but did not eliminate them. With the advent of smartphones the issue of viewers not being able to access a website immediately has become less of an issue, however the trouble of typing in URLs still remained and thus QR codes were used in order to allow redirecting to URLs for instant access. Several QR Code Generators offer an additional feature - Dynamic QR Codes. Dynamic QR Codes can be edited over and over again since they use a placeholder URL which also makes it easier and faster to scan than their counterpart - Static QR Codes

QR codes have been used to establish "virtual stores", where a gallery of product information and QR codes is presented to the customer, e.g. on a train station wall. The customers scan the QR codes, and the products are delivered to their homes. This use started in South Korea,[26] and Argentina,[27] but is currently expanding globally.[28] Walmart, Procter & Gamble and Woolworths have already adopted the Virtual Store concept.[29]

QR codes can be used to store bank account information or credit card information, or they can be specifically designed to work with particular payment provider applications. There are several trial applications of QR code payments across the world.[30][31] In developing countries like India and China[32][33], QR code payment is a very popular and convenient method of making payments.

In November 2012, QR code payments were deployed on a larger scale in the Czech Republic when an open format for payment information exchange — a Short Payment Descriptor — was introduced and endorsed by the Czech Banking Association as the official local solution for QR payments.[34][35] In 2013, the European Payment Council provided guidelines for the EPC QR code enabling SCT initiation within the Eurozone.

QR codes can be used to log into websites: a QR code is shown on the login page on a computer screen, and when a registered user scans it with a verified smartphone, they will automatically be logged in. Authentication is performed by the smartphone which contacts the server. Google tested such a login method in January 2012.[36]

By specifying the SSID, encryption type, password/passphrase, and if the SSID is hidden or not, mobile device users can quickly scan and join networks without having to manually enter the data.[37] Note that this technique is valid for specifying only static SSID passwords (i.e. PSK); dynamic user credentials (i.e. Enterprise/802.1x) cannot be encoded in this manner.

The format of the encoded string is:

WIFI:S:<SSID>;T:<WPA|WEP|>;P:<password>;H:<true|false|>;

Order of fields does not matter. Special characters """ (quotation mark), ";" (semicolon), "," (comma), ":" (colon) and "\" (backslash) should be escaped with a backslash ("\") as in MECARD encoding. For example, if an SSID were "foo;bar\baz", with quotation marks part of the literal SSID name itself, this would be encoded as: WIFI:S:\"foo\;bar\\baz\";;[38]

As of January 2018, iPhones have this feature built into the camera app under iOS 11.x. Android users may have the feature built into one of the device's stock apps (e.g. Samsung Galaxy S8/S8+/Note8 users can launch the stock browser, tap the browser's 3-dot menu, then choose "Scan QR code") or can install one of several available free apps such as "Barcode Scanner" or "QR Droid" to perform the QR Wi-Fi join.

In 2008, Ishinokoe in Yamanashi Prefecture, Japan began to sell tombstones with QR codes produced by IT DeSign, where the code leads to a virtual grave site of the deceased.[39][40][41] Other companies, such as Wisconsin based Interactive Headstones, have begun implementing QR codes into tombstones.[42] In 2014, the Jewish Cemetery of La Paz in Uruguay began implementing QR codes for tombstones.[43]

QR codes are also used in scanning TOTP secrets to generate time-based one-time passwords.

Japanese immigration landing permission with a QR code at the bottom. The QR code content is encrypted.

Encrypted QR codes, which are not very common, have a few applications. For example, the Japanese immigration system uses encrypted QR codes on landing permission stamps in passports.[44][45]

Popular video games, such as Fez, The Talos Principle, and Watch Dogs, have incorporated QR codes as story and/or gameplay elements.[46][47] Mobile games such as Munzee use geolocation in combination with QR codes to create a game that is played in the real world by scanning QR stickers in physical location.[48]

QR Codes have been used by various retail outlets that have loyalty programs. Usually, these programs are in the form of an app that users can download onto their phone and comes with a feature to scan QR codes, which are found printed on the receipt received when making a purchase, allowing users to collect award points simply by scanning the code.

Dynamic QR Codes are used by brands[49] and governments[50] to let consumers, retailers and distributors verify the authenticity of the products. However, the security level is limited since valid QR Codes are easily reproduced on fake products, even though the analysis of data generated as a result of QR Code scanning can be used to detect illicit activity[51]. A higher security level can be attained by embedding a digital watermark or copy detection pattern into the QR Code, which can be authenticated by scanning with a specific app.

The amount of data that can be stored in the QR code symbol depends on the datatype (mode, or input character set), version (1, ..., 40, indicating the overall dimensions of the symbol, i.e. 4 × version number + 17 dots on each side), and error correction level. The maximum storage capacities occur for version 40 and error correction level L (low), denoted by 40-L:[6][52]

Here are some sample QR code symbols:

• 
  Version 1 (21×21). Content: "Ver1"
• 
  Version 2 (25×25). Content: "Version 2"
• 
  Version 3 (29×29). Content: "Version 3 QR Code"
• 
  Version 4 (33×33). Content: "Version 4 QR Code, up to 50 char"
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  Version 10 (57×57). Content: "Version 10 QR Code, up to 174 char at H Level, with 57x57 modules and plenty of error-correction to go around. Note that there are additional tracking boxes"
• 
  Version 25 (117×117 enlarged to 640x640) Content: 1,852 characters of ASCII text describing QR Codes
• 
  Version 40 (177×177).

Damaged but still decodable QR code, Link to http://en.m.wikipedia.org

Example of a QR code with artistic embellishment that will still scan correctly thanks to error correction

Codewords are 8 bits long and use the Reed–Solomon error correction algorithm with four error correction levels. The higher the error correction level, the less storage capacity. The following table lists the approximate error correction capability at each of the four levels:

In larger QR symbols, the message is broken up into several Reed–Solomon code blocks. The block size is chosen so that at most 15 errors can be corrected in each block; this limits the complexity of the decoding algorithm. The code blocks are then interleaved together, making it less likely that localized damage to a QR symbol will overwhelm the capacity of any single block.

Due to error correction, it is possible to create artistic QR codes that still scan correctly, but contain intentional errors to make them more readable or attractive to the human eye, as well as to incorporate colors, logos, and other features into the QR code block.[54][55]

It is also possible to design artistic QR codes without reducing the error correction capacity by manipulating the underlying mathematical constructs.[56][57]

The format information records two things: the error correction level and the mask pattern used for the symbol. Masking is used to break up patterns in the data area that might confuse a scanner, such as large blank areas or misleading features that look like the locator marks. The mask patterns are defined on a grid that is repeated as necessary to cover the whole symbol. Modules corresponding to the dark areas of the mask are inverted. The format information is protected from errors with a BCH code, and two complete copies are included in each QR symbol.[2]

The message dataset is placed from right to left in a zigzag pattern, as shown below. In larger symbols, this is complicated by the presence of the alignment patterns and the use of multiple interleaved error-correction blocks.

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  Meaning of format information. Encoding: In the above figure, the format information is protected by a (15,5) BCH code, which can correct up to 3 bit errors. The total length of the code is 15 bits, and 5 indicates the number of data bits (EC level plus mask pattern). 10 extra bits are used for error correction. The mask for these 10 bits is: [1001010101] (excludes the fixed pattern squares). The first 5 bits are unmasked.
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  Message placement within a QR symbol. The message is encoded using a (255,249) Reed Solomon code (shortened to (24,18) code by using "padding") which can correct up to 3 byte errors.
• 
  Larger symbol illustrating interleaved blocks. The message has 26 data bytes and is encoded using two Reed-Solomon code blocks. Each block is a (255,233) Reed Solomon code (shortened to (35,13) code), which can correct up to 11 byte errors in a single burst, containing 13 data bytes and 22 "parity" bytes appended to the data bytes. The two 35-byte Reed-Solomon code blocks are interleaved so it can correct up to 22 byte errors in a single burst (resulting in a total of 70 code bytes). The symbol achieves level H error correction

The general structure of a QR encoding is as a sequence of 4 bit indicators with payload length dependent on the indicator mode (e.g. byte encoding payload length is dependent on the first byte).[58]

Note:

• Character Count Indicator depends on how many modules are in a QR code (Symbol Version).
• ECI Assignment number Size:
  • 8 × 1 bits if ECI Assignment Bitstream starts with '0'
  • 8 × 2 bits if ECI Assignment Bitstream starts with '10'
  • 8 × 3 bits if ECI Assignment Bitstream starts with '110'

Four-bit indicators are used to select the encoding mode and convey other information.

Encoding modes can be mixed as needed within a QR symbol. (e.g., a url with a long string of alphanumeric characters )

[ Mode Indicator][ Mode bitstream ] --> [ Mode Indicator][ Mode bitstream ] --> etc... --> [ 0000 End of message (Terminator) ]

After every indicator that selects an encoding mode is a length field that tells how many characters are encoded in that mode. The number of bits in the length field depends on the encoding and the symbol version.

Alphanumeric encoding mode stores a message more compactly than the byte mode can, but cannot store lower-case letters and has only a limited selection of punctuation marks, which are sufficient for rudimentary web addresses. Two characters are coded in an 11-bit value by this formula:

V = 45 × C₁ + C₂

This has the exception that the last character in an alphanumeric string with an odd length is read as a 6-bit value instead.

The following images offer more information about the QR code.

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  1 — Introduction
• 
  2 — Structure
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  3 — Layout & Encoding
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  4 — Levels & Masks
• 
  5 — Protocols

Model 1 QR code is an older version of the specification. It is visually similar to the widely seen model 2 codes, but lacks alignment patterns.

Micro QR code is a smaller version of the QR code standard for applications where symbol size is limited. There are four different versions (sizes) of Micro QR codes: the smallest is 11×11 modules; the largest can hold 35 numeric characters.[59]

• 
  Micro QR code example
• 
  Micro QR code functional regions
• 
  Model 1 QR code example
• 
  Model 1 QR code functional regions

IQR Code is an alternative to existing QR codes developed by Denso Wave. IQR codes can be created in square or rectangular formations; this is intended for situations where a rectangular barcode would otherwise be more appropriate, such as cylindrical objects. IQR codes can fit the same amount of information in 30% less space. There are 61 versions of square IQR codes, and 15 versions of rectangular codes. For squares, the minimum size is 9x9 modules; rectangles have a minimum of 19x5 modules. IQR codes add error correction level S, which allows for 50% error correction.[60] IQR Codes have not yet been given an ISO specification, and only proprietary Denso Wave products can create or read IQR codes.[61]

Secure Quick Response code (SQRC) is a type of QR code that contains a "private data" segment after the terminator instead of the specified filler bytes "ec 11".[62] This private data segment must be deciphered with an encryption key. This can be used to store private information and to manage company's internal information.[63]

FrameQR is a QR code with a “canvas area” that can be flexibly used. In the center of this code is the canvas area, where graphics, letters, and more can be flexibly arranged, making it possible to lay out the code without losing the design of illustrations, photos, etc.[64]

Samples of the High Capacity Colored 2-Dimensional (HCC2D) code: (a) 4-color HCC2D code and (b) 8-color HCC2D code.

Researchers have proposed a new High Capacity Colored 2-Dimensional (HCC2D) Code, which builds upon a QR code basis for preserving the QR robustness to distortions and uses colors for increasing data density (at this stage it is still in prototyping phase). The HCC2D code specification is described in details in Querini et al. (2014),[65] while techniques for color classification of HCC2D code cells are described in detail in Querini and Italiano (2014),[66] which is an extended version of Querini and Italiano (2013).[67]

Introducing colors into QR codes requires addressing additional issues. In particular, during QR code reading only the brightness information is taken into account, while HCC2D codes have to cope with chromatic distortions during the decoding phase. In order to ensure adaptation to chromatic distortions which arise in each scanned code, HCC2D codes make use of an additional field: the Color Palette Pattern. This is because color cells of a Color Palette Pattern are supposed to be distorted in the same way as color cells of the Encoding Region. Replicated color palettes are used for training machine learning classifiers.

Wikipedia greetings with link encoded using JAB code.

It is a color 2D matrix symbology made of colorful square modules arranged in either square or rectangle grids made by Fraunhofer SIT. [68] JAB code contains one master symbol and optionally multiple slave symbols. Master one contains four finder patterns located at the corners of the symbol.[69] This project is open source with source code released under GNU LGPL v2.1 license. [70]